1. Field of the Invention
The invention relates to a method for operating an internal combustion engine and to a control device for carrying out the method.
2. Description of the Related Art
DE 10 2007 046 655 A1 discloses an internal combustion engine that has a cylinder row of multiple cylinders. Each cylinder of the cylinder row has multiple outlet valves for exhaust gas. More particularly, a first exhaust-gas duct couples first outlet valves of the cylinders of the cylinder row to a first turbine of a first exhaust-gas turbocharger, and a second outlet duct couples second outlet valves to a turbine of a second exhaust-gas turbocharger. A first charge-air line couples a compressor of the first exhaust-gas turbocharger to the cylinders of the cylinder row, and a second charge-air line couples a compressor of the second exhaust-gas turbocharger to the cylinders of the cylinder row. Exhaust gas exiting the cylinders of the internal combustion engine is conducted either exclusively via the first exhaust-gas turbocharger or alternatively via both the first and second exhaust-gas turbochargers. The two exhaust-gas turbochargers are connected in parallel with one another. When the exhaust gas is conducted exclusively via the turbine of the first exhaust-gas turbocharger, the exhaust gas exits the cylinders exclusively via the first outlet valves of said cylinders. By contrast, when the exhaust gas is conducted in parallel via the turbines of both exhaust-gas turbochargers, the exhaust gas can exit the cylinders of the cylinder row via both outlet valves in parallel. Such an internal combustion engine also is referred to as an internal combustion engine with sequential supercharging.
Internal combustion engines with sequential supercharging are known from DE 10 2007 046 655 A1, DE 10 2007 046 656 A1 and DE 10 2008 036 308 B4. However, there is a demand for improving the operation of such an internal combustion engine to utilize the sequential supercharging optimally.
It is an object of the invention to provide a novel method for operating an internal combustion engine, and a control device for carrying out the method.